1. Field of the Invention
The invention relates to di-(D-tryptophyl and/or tetrahydropyridoinolylcarbonyl)-containing peptide amides which are useful as Substance P agonists and/or antagonists and are therefore useful as antihypertensives and/or analgesics.
2. Information Disclosure Statement
Substance P (SP) is an endogenous undecapeptide amide and a putative neurotransmitter of mammalian central nervous systems (Sandberg et al., J. Med. Chem., vol. 25, no. 9, pp. 1009-1015, 1982) having the following structural formula, wherein the amino acid units are numbered from 1 through 11 beginning with the N-terminal amino acid: ##STR1## The hexapeptide amide having the structural formula ##STR2## is referred to as SP.sub.6-11.
Hansen et al. U.S. Pat. No. 4,472,305 issued Sept. 18, 1984 describes Substance P agonist and/or antagonist hexapeptide amides related to SP.sub.6-11 including the product of example 17 having in its free base form the structural formula EQU H--Pro--DTrp--Phe--DTrp--Leu--Met--NH.sub.2.
Yabe et al. (Chem. Pharm. Bull., vol. 25, pp. 2731-2734, 1977) describes the peptide having the structural formula EQU Z--Tca--Met--Asp--Phe--NH.sub.2
having gastric juice stimulating activity, which is otherwise described therein as Tca-tetragastrin. Tca (H--Tca--OH) is defined as 1,2,3,4-tetrahydro-.beta.-carboline-3-carboxylic acid having the L-configuration.
Yabe et al. (Chem. Pharm. Bull., vol. 26, pp. 993-997, 1978) describes Tca.sup.8 -somastatin (somastatin is a cyclic tetradecapeptide), which showed inhibition of thyrotropin releasing hormone (TRH)-induced thyrotropin stimulating hormone (TSH) release in the rat.